Conserving Collected Stormwater

It has become more common in our area to use an irrigation system as a way to dispose of collected stormwater.  On paper this sounds like a very environmentally friendly solution.  However, many engineers and architects are failing to see the the full potential of installing an irrigation system.  Their narratives discuss disposal of the water and dosage information.  One could easily confuse their irrigation narratives with that of an on-site septic system.  It is very clear that their goal is to get rid of the water as soon as possible.  However, is this sustainable?  If we install solar panels, and we have multiple sunny days, should we turn on all the lights to get rid of our abundance of collected electricity?

On a recent project, we were able to irrigate most of the site, with only collected stormwater.  The irrigation system is programmed to operate above the plant material ET rates and below maximum soil loading rates.  The basin will be completely drained once a year by the irrigation system.  We estimate this to occur in October.  If the quick disposal method were followed, we would irrigate at the maximum soil loading rate.  We estimated that we would run out of water 4 months of the year, probably resulting in some brown turf.

Which way do you feel is more sustainable and looks holistically at site design?

Final Irrigation Walk Through

So you are the project lead and you were just told that the irrigation system is complete.  The budget is tight, so you decide that you can handle this task.  You think to yourself:  "Hey, I know enough to be dangerous.  It is just irrigation.  I can tell if it throws water!"

The irrigation contractor walks you through the system.  Shows you the backflow preventer, maybe opens a valve box or two, maybe a pump station, controller, and then turns on and off each zone.  You see the sprinklers shooting water and think it looks great.  You sign off on it, and the contractor gets paid.  The project is completed.  You made sure your client got what they paid for, right?

• Did you check to see if the pipe was the proper size?
• Check pressure available at the distal sprinkler?
• Inspect solvent-weld joints to make sure solvent and primer was not running down the pipe?
• Did the contractor use primer and/or lube?
• Teflon tape?
• Proper schedule of fittings?
• Were the thrust blocks installed against undistrubed soil?  Did they open the bag and mix the cement?
• Was the controller properly programmed for the climate in your area?
• Was the control wire and splice suitable for direct bury?
• Are the valve boxes dry?
• Are the valve boxes and sprinklers installed at grade?
• Is the drip tubing properly secured and covered?
• Are different nozzles used for different arcs?
• ETC.....

The standard nozzle for most mid-range rotors emits 3.0 gallons per minute.  If a zone has one rotor set at 90 degrees and the rest set at 180 degrees the nozzle on the 90 degree rotor should be reduced to emit 1.5 gallons per minute.  If nozzle is not changed, that one sprinkler uses 1.5 gallons per minute more than needed.  If the zone is scheduled to operate 20 minutes daily, then the irrigation system uses at least 30 gallons more than it needs to daily.  That would result in 930 gallons of wasted water for the month of July, for that one zone.

If this is the result of just one misplaced nozzle, what is the effect of the other items mentioned?

Reducing Water Use on Synthetic Turf Fields

There is no typo in the title.  Synthetic turf requires less than its natural counterpart, but does not eliminate water use.  Cleaning, cooling, and improving playability is just a few things water is used for on a synthetic field.  Water is usually applied to the field with hoses, water canons, traveling sprinklers, and/or underground sprinklers.  

Below is a link to an article that appeared in SportTurf discussing a recent renovation to a field at Princeton University.  The renovation included installing underground sprinklers to wet the field prior to field hockey games.  With the new system, it takes 1,200 gallons of water to saturate the field.  Previously they applied water using a traveling sprinkler (water reel).  To saturate the field with the traveling sprinkler it required 12,000 gallons of water.  Again, that is not a typo!

http://read.dmtmag.com/i/96775/21

The Solution to All of Our Environmental Concerns!

Does it help the environment installing synthetic turf, in an area where there is an abundant water supply, and has had a healthy stand of natural turf for years?

Should an athletic field be kept as natural turf if it is mostly dirt and mud from over use?

Is consuming organic produce, that needs to be transported 700 miles, more environmentally friendly than conventionally grown produce from a neighboring farm?

Does the energy saved from a light bulb made in China compensate for the fossil fuels burned to get the bulb to your house?

Are the same maximum turf limits recommended in Arizona best for a site in Pennsylvania?

I could keep going.  At the bottom of this posting there is a link to another blog.  It does not talk about irrigation, water conservation, landscaping, or site development.  What it does is challenge us to think.  We as design professionals are heavily marketed by companies offering all types of "green" solutions.  What is best for our clients and the environment is not always the latest and greatest, and does not always result it a pretty plaque in a lobby.  Just something to think about.

http://www.totallandscapecare.com/the-truth-about-diesel/

Rainwater Harvesting and Water Conservation

In early November I attended the Irrigation Association’s National Irrigation Show and Educational Conference.  Attendees have the opportunity to attend educational seminars, and to see some of the latest products in irrigation.  Most new products offer water conservation improvements from those utilized in the past.  One heavily marketed water conservation method is rainwater or stormwater harvesting.  This is the practice of catching, and storing, water that would typically be lost to runoff from non-pervious surfaces such as roofs or parking lots.  The stored water is then able to be utilized for non-potable uses such as irrigation.  This is a wonderful way to conserve water, but does have one major downfall.  The cost of providing storage for this captured water is expensive, and the return on investment period is typically longer than many like to see.  Some projects can justify the added expense, because it is part of the stormwater management plan, LEED certification, and/or the organization feels strongly about water conservation.  However, only 5% of our projects fall into one of these three categories.  Does this mean that unless one spends large amounts of money that water requirements for irrigation can not be reduced?  Absolutely not!  Below are several inexpensive methods to reduce landscape water use:  

• Good head to head coverage.  Sprinklers should be spaced so that the water stream from one touches another sprinkler.  This provides good uniform distribution of water throughout the irrigated area.  This is the way the manufacturer’s design the sprinklers.  Stretching the spacing or eliminating a sprinkler reduces distribution uniformity.  The result is longer run times to compensate for the dry areas, and higher water use.  
• Proper sprinkler inlet pressure.  Too much or too low of water pressure has a negative effect on sprinkler performance.  One produces a fine mist that is lost in the wind and evaporation.  The other provides a beautiful green donut pattern in turf areas.  Either results in a higher water bill.  
• Reduced flow rate spray nozzles.  Old style spray nozzles, fixed and variable arc, have a very high flow rate.  A flow rate much higher than most soils can handle resulting in unwanted run-off.  Most manufacturer’s now make spray nozzles that water at a much more manageable flow rate.
• ET-based / soil moisture sensors and smart controllers.  This technology has received a lot of negative and positive publicity.  A lot of the negative opinions of these controllers and technologies are related to the area of the country one resides in and sometimes mis-management.  My opinion concerning smart controllers and sensors are mostly positive.  Our area of the country “supplements” water requirements for landscapes.  Typically controllers are set in the spring for water requirements in July and turned off in October.  Water requirements are greatest in July.  Having a controller reduce watering times, based on current weather or soil conditions, has a huge potential to minimize water use.
• Rain sensors.  Watering is suspended when a pre-set amount of rainfall is received.  Rain sensors or switches are so inexpensive I can not think of a situation when one should not be installed.

Understanding Design/Build Irrigation Bids

Design/Build Irrigation Bid Request:  Provide a fully functional underground irrigation system to provide 100% coverage for all landscaped areas.  Acceptable manufacturers:  Hunter, Rain Bird, and Toro.

Design/Build Bid Submitted:

1 - Controller = $2,000
20 - Zones = $20,000
200 - Sprinklers = $20,000
Total = $42,000

Above is a common irrigation design/build request and bid submittal.  Sometimes an engineering or architecture firm may include a couple of details they were able to find online.  Sometimes the bidding company may include a few manufacturer cutsheets.  However, this is what is what is typically accepted.

So what is wrong with this?  If this was a true design/build, where is the design?  Could you imagine this being acceptable:

Design/Build Bid Request Sample:  Provide an aesthetically pleasing  landscaped area.  Acceptable suppliers:  ….

Design/Build Bid Submitted:

70 - Retaining Wall Blocks = $2,000
10,000 square feet - turf = $20,000
20 - Trees = $9,000
40 - Shrubs = $9,000
80 - Ground Cover Plants = $2,000
Total = $42,000

The above samples are not meant to take a swipe at the design/build industry.  In some situations, it may be the best solution for the project.  But, the organization that is overseeing the project should not forget the design aspect.  A complete design should be required, and the design should be reviewed by someone familiar with irrigation systems.  If the construction manager is not familiar with irrigation systems, the general contractor should consider talking with an irrigation consultant.  Possibly contracting with the consultant to review the submitted plans and providing some unbiased feedback.  

Many projects in our area are completed based on similar bids and requirements as the above sample.  The irrigation contractor was able to walk away with a pay check.   The general contractor signed off  because they saw water flying.  Unfortunately, due to inefficiencies with the installed irrigation system, it did more harm than good for the landscape!  The end result is usually an irrigation system that has a higher than normal cost of operation, maintenance, and an over/under watered landscape.

No Need for Irrigation in Pennsylvania, We Can Just Handwater

It is now mid July, and I think it is safe to say that this is the hottest and driest summer Central Pennsylvania has experienced in a few years.  Over the past couple of months I have heard a lot of comments about the brown and crunchy lawns around the area.  Here are my two favorites:

We do not need irrigation in Pennsylvania. Well yes and no.  Pennsylvania is not Arizona.  We do not need irrigation to grow grass, however we typically do not receive enough rainfall to sustain healthy turf throughout the summer.  I observe many businesses and homeowners treating their lawns with fertilizers and pesticides.  A healthy lawn is a lawn that has deep roots and dense coverage.  A healthy lawn is accomplished with proper amounts of water and nutrients throughout the growing season.  When both are provided at proper levels, the inputs of both are minimized.  This means that less fertilizer is needed if the lawn receives enough water and less water is needed if the lawn receives the proper amount of nutrients.  A denser lawn suppresses weeds.  I am sure you can see where this discussion is heading!

By hand watering I am reducing my water use.  A well designed, installed, and maintained irrigation system should distribute a uniform amount of water over the irrigated area.  It should do this only when the area requires water, right before one would see signs of water stress.  Hand watering in our area is usually accomplished by placing some sort of sprinkler in the lawn and running it until you remember that it is on, or you have finished talking to your neighbor or coworker.  It typically waters all types of areas like sidewalks, roads, houses... in addition to the lawn.  One usually begins the cycle of hand watering after the lawn becomes brown.  The first problem with this method is the uneven, untimed, uncalculated amount of water being provided to the lawn, or the sidewalk.  The second problem with this method is not watering the lawn until it goes brown, or what is referred to as dormancy.  Once turf goes into dormancy one has to provide it with enough water to convince it that it is safe to start growing again.  This requires a lot more water than it takes to sustain growth.

So does this mean that everyone in Pennsylvania should have an irrigation system?  The answer is no.  Many people are happy with the way lawns grow in Pennsylvania.  My father does not have an irrigation system.  He does not understand why you would water your lawn resulting in the need to mow in July and August.  However, if you are a business or homeowner that spends money to treat their lawn four times a year, or have extra hoses and a couple of sprinklers that you picked-up at your local hardware store, you may want to reconsider your practices.